Sensor having a mesh layer with protrusions, and method

1. A sensor comprising: a grid of bars that are in contact from their bottom at bar crossings with a set of protrusions that are in contact from above with a plurality of intersections, each having a sensing element, of a grid of wires disposed on a base, and a top surface layer that is disposed atop the grid of bars, so that force imparted from above onto the top surface layer is transmitted to the grid of bars and thence to the protrusions, and thence to the intersections of the grid of wires which are thereby compressed between the base and protrusions; and that the protrusions above thereby focus the imparted force directly onto the intersections, including adhesive disposed between the top surface layer and the grid of bars, and between the protrusions and the grid of wires, and between the grid of wires and the base and the top surface layer has a valid amount of rigidity relative to a height of the protrusions where a distance of a deformation of the top surface layer is described by E(bend)=L 3 F/(4wh 3 d), where L is length, w and h are width and height, respectively, F is an applied force and d is the deflection to a load on the top surface layer, so the distance of deformation of the top surface layer is less than the height of the protrusions and the top surface layer never touches the base causing force to be imparted onto the base; and a computer in communication with the grid of wires which causes prompting signals to be sent to the grid of wires and reconstructs a continuous position of force on the surface from interpolation based on data signals received from the grid of wires.

2. The sensor of claim 1 wherein each sensing element includes force sensitive resistive material (FSR).

3. The sensor of claim 2 wherein when force is imparted to the surface layer, each protrusion is aligned to be in contact with a corresponding sensing element.

4. The sensor of claim 3 wherein each protrusion is a rigid bump of plastic, metal, wood or glass and focuses force onto the corresponding sensing element, each protrusion having a shape whose contact with the corresponding sensing element lies exactly upon or inside of the corresponding sensing element.

5. A method for sensing comprising the steps of: imparting force from above onto a top surface layer that is transmitted to a set of grid of bars and thence to a set of protrusions, and thence to a plurality intersections of a grid of wires which are thereby compressed between the base and protrusions, where the set of grid of bars are in contact from their bottom at their bar crossings with the set of protrusions that are in contact from above with the plurality of intersections of the grid of wires disposed on the base; and that the protrusions above thereby focus the imparted force directly onto the intersections, including adhesive disposed between the top surface layer and the grid of bars, and between the protrusions and the grid of wires, and between the grid of wires and the base and the top surface layer has a valid amount of rigidity relative to a height of the protrusions where a distance of a deformation of the top surface layer is described by E(bend)=L 3 F/(4wh 3 d), where L is length, w and h are width and height, respectively, F is an applied force and d is the deflection to a load on the top surface layer, so the distance of deformation of the top surface layer is less than the height of the protrusions and the top surface layer never touches the base causing force to be imparted onto the base; causing prompting signals by a computer in communication with the grid of wires to be sent to the grid of wires; and reconstructing with the computer a continuous position of force on the surface from interpolation based on data signals received from the grid of wires.

6. A method of forming a sensor comprising the steps of: placing a mold made of silicone rubber that contains regularly spaced holes atop an outer side of a surface substrate; pouring a resin into these holes; removing the mold when the resin hardens so the resin forms regularly spaced bumps upon a top surface of the surface substrate; and positioning a top surface layer in place relative to the top surface of the surface substrate, where the top surface layer has a valid amount of rigidity relative to a height of the bumps where a distance of a deformation of the surface layer is described by E(bend)=L3F/(4wh3d), where L is length, w and h are width and height, respectively, F is an applied force and d is the deflection to a load on the top surface layer, so the distance of deformation of the top surface layer is less than the height of the bumps so sensing elements are formed at an intersection of a grid of wires that includes using force sensitive resistive material (FSR) to form an active sensing array, where the bumps are positioned at the location of the sensing elements so that force can be imparted from the touch layer through the bumps to the sensing elements.